Technical Abstract:
Infrared spectroscopy, generally in the form of FTIR, has been used to characterize the organic matter in animal manure and relevant materials or fractions. The FT-IR spectra of most manure samples resemble the Type III spectra of humic substances with strong aliphatic characters. However, the absorption band around 1720 cm-1 is very weak or even disappears in manure spectra, indicating fewer free carboxylic groups in animal manure than in humic substances. FTIR spectroscopy revealed that composting and decomposition of animal manure begin by the degradation of labile organic matter components. Relative spectral intensities, such as the peak ratios of 1650 /2930, 1620 /1110, 1385 /2930, 1650 /1560 and 1511/2930 cm-1, can be used to monitor the change (stability and maturity) in manure organic matter under different management practices. FTIR PAS spectroscopy offers an alternative method to characterize organic matter in animal manure. It requires minimal sample pre-treatment and allows the use of larger amounts of substance in the analysis, thus minimizing the experimental deviations due to heterogeneous characteristics of animal manure. Further modification and verification of this method may provide a fast and cheap method for qualitative and semiquantitative assessments of animal manure from different sources with a wide range of properties.